Martin Thoresen wrote:So you have 1 W5580?
Then with ponder on you are running your system hyperthreaded?
Just curious.
good point!
i assume you're using a quad core CPU?
so A and B play with 4 threads each. the problem with using pondering is that when A plays, and its 4 threads are busy, B also has 4 busy threads pondering. So you have 8 threads running on 4 CPU, which is somewhat suboptimal. It would make more sense to use 2 threads per engine if pondering, or switch pondering to off.
i generally prefer pondering off, as it makes the most sense generally. if B has no pondering feature, here what happens:
1/ A plays: 4 threads thinking, B's 4 threads are idle
2/ B plays: 4 threads thinking, A's 4 threads are pondering
1/ A uses 100% of the CPU resources
2/ both A and B use 50% resources
So pondering on introduces an unjust biais, and favors A in this situation... Which is why I think that pondering on is a silly idea. It comes from the misconception that computers, like humans, should be allowed to think on their opponent's time. But the reasons why this conception is flawed are:
1/ time doesn't affect computer's playing skills in any compararable way to humans. If computer plays in 1 second instead of 10, the quality of the moves will (on average) not be very different. time pressure is a huge factor in human games, but nowhere near as much so in computer games. perhaps computer will reach depth 12 instead of 13 if 1 second i/o 10 second, or something like that, not a big difference
2/ both programs are concurrently running on the same CPU, so when one thinks it sucks up the CPU resources of the other. 2 humans playing have 2 distinct brains, and there's no such interaction.
So I always use pondering off in my rating list for the above mentionned reasons, and I would encourage you to do the same.
